Thread gage having gaging rolls with setting surfaces



p 2, 1 8 P. w; JOHNSON A 2,849,804

THREAD GAGE HAVING GAGING ROLLS WITH SETTING SURFACES Filed March 15,- 1955 F :L l q. E

INVENTOR- PHUL W. JOHNSON H 7' TORNEY-S United States Patent THREAD GAGE HAVING GAGING ROLLS WITH SETTING SURFACES Paul W. Johnson, Bloomfield, Conn., assignor to The Johnson Gage Development Company, Bloomfield, Conn, a corporation of Connecticut Application March 15, 1955, Serial No. 494,472

14 Claims. (Cl. 33-199) The invention relates to both a working thread gage and a master gage, the latter being used to set a working thread gage to the proper dimension or size for gaging threaded parts. The invention also relates to gaging rolls for gages in which a setting surface is provided upon the roll which surface is spaced from the gaging roll axis a distance the same as the pitch radius of the pitch diameter of the gaging ridge or ridges whereby the setting of the working gage or the master gage may be made with a micrometer or a cylindrical plug. Threaded master plugs which are expensive equipment as well as more complex systems are presently used in making the setting of the gages and in addition the calculations involved introduce a possibility of error. With the gage to be described, threaded master plugs and other equipment are dispensed with in the setting of the gage to its proper dimension.

An object of the invention is to construct a gage having a gaging roll with gaging ridges around the periphery thereof and with a setting surface on the roll at the radius of the pitch diameter of the gaging ridge or ridges by means of which a micrometer or a cylindrical plug may be used to accurately and quickly set the gage to the proper dimension.

Another object is to construct a master or working gage having at least three gaging rolls with the gaging rolls described in the preceding statement of objects for accurately and quickly setting the gaging rolls of the gage.

Another object is to construct a gaging roll having at least one gaging ridge around the periphery with a setting surface on the roll at the pitch diameter or spaced from the roll axis by the radius of the pitch diameter by means of which a micrometer or cylindrical plug of the proper diameter may be used to set the rolls to the proper size or spacing when the gaging rolls are mounted on a frame to form a master or working gage.

Other objects of the invention will be more apparent from the following description when taken in connection with the accompanying drawings illustrating preferred embodiments thereof in which:

Figure 1 is a front view of a gage having gaging rolls each roll being provided with a setting surface;

Figure 2 is a side view of the gage of Figure 1;

Figure 3 is a front view of a comparator type of gage with gaging rolls each roll being provided with a setting surface;

Figure 4 is a front view of a tri-roll gage;

Figure 4A is a front view and modified form of an auxiliary setting member for the gage of Figure 4;

Figure 5 is a side view of a go and not-go external thread gage with gaging rolls each roll being provided with a setting surface;

Figure 6 is an end view of another form of ridged gaging roll with a setting surface;

Figure 7 is a front view of a gaging roll with the setting surface spaced axially from the gaging ridges;

Figure 8 is an end view of the gaging roll of Figure 7; and

a r I Figure 9 is an end view of a tri-roll working gage of the comparator type.

Working thread gages are used by an'inspector to test a thread for size and the ability of the thread to assemble with a mating threaded hole. A master gage is used to set the working gage to the desired dimension or dimensions. It is the practice, particularly in the larger sizes, to measure the setting or spacing of the gaging rolls of the gage by using wires in the thread or ridge grooves of each gaging roll and a micrometer to measure across the wires. A master gage when properly set is then used in setting of the thread gaging rolls of a working thread gage such as a working roll snap thread gage. It is not only awkward to set the master gage because of difficulty in maneuvering of the wires and micrometer but in addition some calculations must be entered into to determine the micrometer dimension or reading based upon the desired pitch diameter and the wire diameters. These calculations sometimes entail errors. With the construction to be described, the master and the working gages may be set directly without manipulation of wires and Without the need of entering into any or any wire calculations. For smaller sizes, a threaded master plug is used in making the setting of the gaging rolls and a master plug is needed for each size as well as for all different tolerances for each size. Such master plugs are expensive even when but one is required.

Figures 1 and 2 illustrate a gage, primarily a master gage but which can be used without change as a working gage. The gage comprises a frame 16) of suitable construction, having gaging rolls 11 and 12 spaced from each other at opposite ends of the frame. The gaging rolls have at least one circumferential gaging ridge 14 extending around the periphery thereof which gaging ridge may be a helical ridge conforming in pitch to the screw thread to be tested or gaged although preferably each gaging ridge is planar or not helical. The gaging ridge or ridges illustrated on each gaging rolls are a pair for gaging pitch diameter so that the ridges on one gaging roll engage the flanks of two adjacent gaging ridges of the rolls of a working gage and the gaging ridges on the other cooperating gaging roll of the master gage are formed to engage both flanks or sides of a single gaging ridge of the cooperating gaging roll of a working gage. The rolls will have more gaging ridges for a working gage which is to test over-all assembleability of a thread.

Each gaging roll has a bearing therethrough and is rotatably mounted upon a stud 13 which stud is mounted upon the frame in any desired manner. The stud of at least one gaging roll is mounted for movement of the gaging roll carried thereby towards and away from another or a cooperating gaging roll. The movement of the gaging roll of Figures 1, 2, 4 and 5 is for adjustment of its position relatively to another. The gaging roll 11 is adjustable by any suitable means or construction, the adjusting means particularly illustrated being an eccentric stud 13 upon which the gaging roll is mounted. Illustrative adjustable eccentric studs are shown in the Johnson Patent 1,851,283 and applicants application Serial No. 42,881 which has matured to Patent No. 2,826,821, dated Mar. 18, 1958, and it is the stud of the latter which is illustrated. A screw 15 may be used to secure the stud to the frame, and a headed screw 15a may be used to retain the roll on the stud.

Suitable means are provided to center the gaging roll 12 of a master gage on a gaging roll R of a working gage. This means may be a slidable member 16 which is slidably mounted upon the frame by means of mounting pins 17 which pass through a slot 20 in the member. The slidable member carries a pair of 'spaced pins 13 which are located adjacent to the gaging roll 12, are equidistant U from the axis of the gaging roll and parallel thereto. They center the gaging roll 12 of the master gage upon the gaging roll R of a working gage such as a roll snap gage. A spring 19 projects the slidable member and its pins 18 outwardly away from the gaging roll 12 so that they will press against the gaging roll of the working gage. With therolls of the master gage properly set, and gage roll 12 engaging and centered on a gaging roll of a working gage, the other gaging roll 11 of the master is passed under the other gaging roll of a working gage to test its setting. If the gaging rolls of the working gage are not properly set for size or spacing, then one roll is adjusted and the master gage is again passed between the rolls to again test its setting.

Heretofore these gaging rolls are tested as to setting by means of a wire in each of a pair of adjacent grooves between the gaging ridges of each spaced gaging roll and then measuring the distance across the wires with a micrometer. v In order to avoid the manipulation of wires and any wire calculation in determining the micrometer setting in which errors can and do occur, each gaging roll has a setting surface shown as a flat surface 22 across at least one gaging ridge which flat, is tangent to the pitch diameter circle of the gagingridge. The setting surface may also be expressed as spaced from the roll axis C, a distance the same as the radius of the pitch diameter of the gaging ridge. If the setting surface is fiat, it is normal to the radius. The setting of the gaging rolls of the master gage therefore can be measured merely by measuring with a micrometer across the flat surfaces 22 and adjusting the spacing between the cooperating gaging rolls until it is of the proper dimension. This master gage may .then be used to set or test the spacing between the cooperating gaging rolls of a Working gage such as of a roll snap gage.

The gage of Figures 1 and 2 may also serve as a working gage to test an external thread. When so used the setting surfaces are used in setting the gaging roll to the proper setting in one of two ways, by using a micrometer or by using a cylindrical plug. With the pitch diameter of the external thread known, the pitch diameters of the gaging ridges of the two gaging rolls are added thereto which gives the micrometer reading across the setting surfaces 22 for a proper dimension or setting and the stud of one gaging roll is adjusted until this micrometer reading is secured. By turning the setting surfaces inwardly facing each other a cylindrical plug of the pitch diameter of the test thread is used to test the setting of the gaging rolls. For large sizes .of thread such plugs are not usually used.

Figure 3 illustrates a comparator type of gage; that is, the gaging roll 11 is carried .on an arm which arm is mounted on a pivot 26. The pivot 26 is carried by a frame 27. A dial indicator 28 is mounted on the gage to indicate the movement or position of the arm and hence of the gaging roll 11 such as by the indicator being carried by the frame and its operating point 29 engaging the arm 25. Preferably the distance between the point of engagement of the operating point 29 from the center of the pivot 26 is the same as the distance from the center of the pivot to the center of the gaging roll 11. The readings on the dial then are direct readings of the movement or position of the gaging roll 11. A spring 30 propels the arm 25 so that the gaging roll 11 is propelled upwardly or away from the gaging roll 12. When serving as a master gage to set a working gage, the centering means or the slidingmember 16 with its pins 18 is used to center this roll on the gaging roll of a working gage as described for the gage of Figure 1. By removing. the centering means the gage may serve as a working gage for internal threads. A compressivespring30r to move the gage roll 11 towards the cooperating-gagin'groll 12 enables the gage to be used as a comparator'working gage for external threadsalthough forsuch gage it would be desirable to mount the indicator on the arm. A stop 4 screw 31 may be provided to limit the movement of the arm.

The gage of Figure 3 is set by putting the anvils of an ordinary micrometer set at the desired dimension on the setting or fiat surfaces 22 of the gaging rolls 11 and 12. The dial of the dial indicator 28 is then rotated so that the pointer 32 is on zero reading after which any variation in the reading from zero when the master gage is applied to a working gage indicates the setting of the rolls of a working gage and would indicate the difference in setting between the go andnot-go rolls of a working gage of this type. The gage of Figure 3 may also serve as a working gage and may be set in the same manner to its proper dimension by using a cylindrical setting plug across inwardly directing setting surfaces or flats or by using a micrometer across the setting flats as shown and subtracting the pitch diameters of the two gaging rolls from the reading.

Each of the gages of Figures 1 to 3 inclusive may also serve as a working gage in which case the flats 22 face towards each other in setting it as a working gage and may be set to proper spacing by passing therebetween a cylindrical plug of the same diameter as the desired pitch diameter asa test of the roll setting. Alternatively it may be set with the setting surfaces as shown and measuring the dimension across the setting surfaces 22 with a micrometer from which reading the pitch diameters of two gaging rolls are subtracted to give the working gage setting.

Figure 4v is a gage designed for; setting a gage having at least three gaging rolls, thatparticularly illustrated being a tri-roll gage with the rolls spaced apart. The frame 33 may be a three-arm frame at the end of each arm of which is carried a gaging roll 34, 35 and 36 respectively. These rolls are identical with the rolls 11 and 12 and each has a setting surface Oil-the, gaging ridges on the pitch diameter as previouslydescribed which surface is shown as a setting flat 22. Each gaging roll is adjustably mounted such as with. an-eccentric stud 13 for moving or setting the stud and theroll carried thereby to the desired dimension or spacing. it is difficult to set the gage rolls with a micrometer directly across the gaging rolls of the-gage and consequently in order to simplify the setting of the gaging rolls, the frame carries a rotatable setting or reference member 37 having a setting surface which is preferably a setting flat 38 on the center or axis thereof. In order to set this gage, the distance betweenthesetting surface or flat 33 and the setting surface or fiat 22 of roll- 36 is set to the radius of the desired pitch diameter and checking the spacing with a micrometer, after which the setting or reference member 37 is turned to bring the fiat 38 parallel with the flat 22 of roll 34 .or at right angles to a radial line through the center of the gaging roll and this gaging roll is set to the same radius of the desired pitch diameter. The same operation is performed with respect to the gaging roll 35 so that all three rolls are set on the same pitch radius and hence all rolls are set to the pitch diameter of the desired thread. Since the settings or measurements are made from or related to a radial line through the center of the roll, the setting surface is in radial alignment with the roll. Centering means 16, 18 is provided for two of the gaging rolls when this gage is to serve as a master setting gage to set the tri-rolls of a working gage. This gage may also serve as a working gage.

The reference member may be a fixed member 52 as shown in Figure 4A which is substituted formember 37, with a setting surface or flat 53, 54 and 55 for each gaging roll 34, 35 and 36 respectively. The micrometer reading between the respective surface on the fixed reference-member 52 .and its cooperating gaging roll must be increased by the dimension between the respective surface and the center 56 of member 52. Bymaking'this dimension the same for all surfaces, but one micrometer setting or reading will serve for setting all gaging rolls.

Figure illustrates a common working gage of the go and not-go roll snap type. The gaging rolls 11a and 12a carried by the frame 39 comprise the go gage or portion and gaging rolls 11b and 12b comprise the not-go gage or portion. In other words a test thread within the acceptable tolerance or thread diameter variation set into the gage will pass through the rolls 11a, 12a but will not pass through the rolls 11b, 12b. These rolls are the same as rolls 11 and 12 of the other figures. The setting of the go rolls is checked as to their proper spacing by passing a plain cylindrical setting plug, of the same diameter as the maximum allowable pitch diameter of the thread to be tested, between the setting flats 22. A plain cylindrical plug of a diameter such that a screw of minimum allowable pitch diameter will not pass therethrough is used similarly to set the spacing or dimension of the not-go gaging rolls 11b and 12b. Expensive thread Zplug gages are now used in making these settings and with the setting surfaces disclosed herein these expensive master setting plugs are not needed. The gaging rolls of Figure 5 may also be checked for their proper setting by turning the rolls so that the setting surfaces 22 face away from each other. When the reading of a micrometer across the setting flats equals the desiredpitch diameter plus the pitch diameters of the two gaging rolls, then the gaging rolls are spaced apart the proper gaging distance.

Figure 6 shows a gaging roll 40 having a groove extending across the gaging ridge or ridges 41 to a depth so that its inner surface or face 42 is on the pitch diameter. The surface 42 of the groove may serve as a setting surface. Preferably a test bar 43 of known dimension is set in the groove and a micrometer reading across the setting surfaces or flats or auxiliary setting surfaces 44 of two spaced gaging rolls is used to set the gage. The micrometer reading will be the desired pitch diameter of the thread plus, the radial dimension of two bars 43. The bottom surface 42 of the groove need not be fiat. The roll has a bearing 45 therethrough for rotatably mounting the same on a stud of any of the gages illustrated.

Figures 7 and 8 illustrate a gaging roll 49 in which the setting surface 46 is carried at the side of the gaging ridges 47. In this construction no part of the gaging surface of the gaging ridges is lost. This setting surface is located far enough away from the ridges or is narrow and located so that it does not interfere with the gage setting operation or testing. The roll has a bearing 48 therethrough for rotatably mounting the same on a stud of any of the gages illustrated.

A tri-roll working gage is shown in Figure 9 as illustrative of any type of tri-roll or multiroll gage. The type of gage particularly illustrated is a known comparator type having a frame 59 upon which a pivoted frame F 60 is pivotally mounted upon a pivot means 61. A pair of spaced studs is carried by the pivoted frame upon each of which is rotatably mounted a gaging roll 11. Cooperative gaging means cooperates with the pair of gaging rolls 11 including at least one other stud carried by the frame upon which is mounted a gaging roll 12. For a comparator type of gage this additional stud and gaging roll 12 is mounted for movement towards and from the pair of rolls 11 carried by the pivoted frame such as by being carried by a lever 62 mounted on the frame 59 upon a pivot means 63. For a comparator type of gage an indicator 64 is carried by the frame 59 and engages the lever to indicate the position of the lever and hence the position of the gaging roll 12. Also for a comparator type of multiroll gage as illustrated in Figure 9, a stop 65 is provided to limit the movement of the pivoted frame 60 to a central or gaging position for a test part at or approximately on a line through the center of the pivot means 61 and the center of the gaging roll 12 or its stud.

Each of the gaging rolls 11 and 12 has a setting sur-- face as described and that shown is a setting flat 22 across each roll ridge or ridges of each roll. A plain cylindrical plug of the proper diameter is inserted into the gage and all of the rolls are turned until each setting surface thereeon engages the plug at the tangent point which can easily be felt. The gage is then set to this plug. For the comparator gage shown this setting is made by turning the dial of the indicator until it reads 0 for the plug. The gage is set therefore with an inexpensive cylindrical plug rather than an expensive threaded plug as heretofore used.

Figures 1, 2, 4 and 5 illustrate gages in which at least one gage roll is movable towards and away from another gage roll in order to secure adjustment of the setting of the gage roll. Figure 3 illustrates a gage in which one gage roll is movable towards and away from another gage roll for comparator gaging of a test part or for serving as a comparator master gage in the setting of a working gage such as a pair of go and not-go gaging rolls. Figure 9 also shows a movable roll 12 for comparator gaging of a test part. The term movement of at least one gaging roll relatively to another gaging roll is intended to comprehend or encompass the adjusting movement or the comparator movement or both.

In all gages illustrated, the rolls are for straight threads; however, by using taper gaging rolls the gages may be used as master gages for setting taper thread working gages or as working gages for taper threads. In all gages the rolls may have a greater number of gaging ridges although for a master gage it is desirable that the rolls be of a type as illustrated for testing pitch diameter. Any form of adjusting means may be used to adjust the spacing of the gaging rolls and the eccentric stud is merely illustrative thereof.

This invention is presented to till a need for an improved thread gage having gaging rolls with setting surfaces therein and the gaging rolls. It is understood that various modifications in structure, as well as changes in mode of operation, assembly, and manner of use, may and often do occur to those skilled in the art, especially after benefitting from the teachings of an invention. Hence, it will be understood that this disclosure is illustrative of preferred means of embodying the invention in useful form by explaining the construction, operation and advantages thereof.

What isclaimed is:

l. A gage comprising a frame, a plurality of studs mounted upon the frame in spaced relation, means mounting at least one stud on the frame for movement towards and from another stud, a gaging roll rotatably mounted on each stud and having a center axis, at least one ci'rcumferential thread gaging ridge upon the periphery of each roll and having a pitch diameter, and a flat setting surface carried by each gaging roll at a distance from the center axis of the gaging roll the same as the radius of the pitch diameter of the thread gaging ridge, each flat setting surface extending at right angles to a line through the center axis of the gaging roll.

2. A gage as in claim 1 in which the flat surface is carried by at least one of the thread gaging ridges.

3. A master gage as in claim 1 including spaced centering means carried by the frame and adjacent one of the gaging rolls on the other side of the roll from the cooperating roll, the centering means being spaced equidistantly from a line passing through the centers of the gaging rolls and from the center of the gaging roll to center the latter upon a gaging roll of a working gage.

4. A gage as in claim 3 including a pivoted lever carried by the frame, one of the studs being carried by the lever spaced from its pivot, and a dial indicator engaging and operated by the movement of the lever.

5. A gage comprising a frame, a plurality of studs mounted upon the frame in spaced relation, means mounting at least one stud on the, frame for movement towards and from another stud, a gaging-roll rotatably mounted on each stud and having a center axis, at least one circumferential thread gaging ridge upon the periphery of each roll and having a pitch diameter, and each gaging roll having a setting groove extending across said thread gaging ridge with the bottom of the groove at a distance from the center axis of the gaging roll the same as the radius of the pitch diameter of the thread gaging ridge,

6. A gage as in claim including a setting bar received in each groove and having a thickness providing a setting surface above said thread gagingridge.

7. A gage comprising a frame, at least three studs mountedupon the frame in spaced relation and uniform angular relation, means mounting at least two studs on the frame for movement towards and from another stud, Y

a gaging roll rotatably mounted on each stud and having a center axis, at least one circumferential thread gaging ridge upon the periphery of each roll and having a pitch diameter, a set-ting surfacecarried by each gaging roll at a distance from the center axis of the gaging roll the same as the radius of the pitch diameter of the thread gaging ridge, and a cooperating setting member carried by the frame centrally of the gaging rolls and having at least one cooperatingsetting surface in radial alignment. with the -setting-surface on the gaging rolls.

8. A gage as in claim- 7 in which the cooperating setting member is rotatably mounted on the frame at the center of the gage and has a single cooperating setting surface on-the member located at right angles to a line through thecenterof the setting member.

9. A gage as in claim 7 in which the cooperating setting member is fixed to the frame and has a cooperating setting surface for each gaging roller.

10. A gaging member comprising a cylindrical gaging roll having a center axis and a bearing through the roll for rotatably mountingthe same on a stud, at least one thread gaging ridge extending circumferentially around the periphery of the roll and-having a pitch diameter, and a flat settingsurface carried by at least one gaging ridge of the roll at a distance from the center axis of the roll which distance is the same as the radius of the pitch diameter of the thread gaging ridge, the setting surface being at right angles to a line through the center axis of the gaging roll.

11. A gaging member as in claim 10 in which the setting surface is formed by a groove extending across the .gagingridges .with the bottom thereof providing the setting surface, and a bar received in the groove and having an.;auxiliary setting surface.

12. A gage comprising a frame, a pivoted frame pivotally mounted upon-the frame,- a pair 'of studs mounted upon the pivoted frame in-spacedrelation, at least one other stud mounted'upon' the frame, means mounting atleast one studon the frame spaced from the pair of studs on-thepivoted frame, a gaging roll rotatably mountedon each-stud and having-a center'axis, at least one circumferential'thread gaging ridge upon the periphery of each roll and-having a pitch diameter, and a setting surface across'said thread gaging ridge of each gaging roll-with the surface'at a 'distancefrom the center axis of the gaging roll the same as the radius of the pitch diameter of the thread gaging ridge.

13. A gage comprising a frame, a pivoted frame pivotally mounted upon-the frame, a pair of studs mounted upon the pivoted frame in'spaced relation, means mount ing at least one stud onthe frame spaced-from the pair of 'studson the pivoted frame' and for movement to wards and--from-t;he pair of studs on the pivoted'frarne when in gaging position; a gaging roll rotatably mounted on each stud and having a center axis, at least one circumferential thread gaging ridge upon the periphery of each roll and having a pitch diameter, and a setting surface across said thread gaging ridge'of each gaging roll with the surface at a distance from the center axis of the gaging roll the same as the radius of the pitch diameter of the thread gaging ridge.

14. A gage comprising a frame, a pivoted framepivotally mounted upon the frame, a pair of studs mounted upon the pivoted frame in spaced relation, a lever pivotally mounted on the frame, means mounting at least one stud on the lever spaced from'the pivot therefor for movement towards and from the pair of studs on the pivoted-frame when in gaging position, a gaging roll rotatably mounted on each stud and having a center axis, at least one circumferential thread gaging ridge upon the periphery of each roll and having a pitch diameter, and a setting surface across said thread gaging ridge of each gaging roll with the surface at a distance from the center axis of the gaging roll the same as the radius of the pitch diameter of the thread gaging ridge.

References'Cited in the file of this patent- UNITED STATES PATENTS 1,851,283 C. Johnson Mar. 29, 1932 1,930,558 S. Johnson Oct. 17, 1933 2,331,757. Anders Oct. 12, 1943 2,348,712 Dahlerup May 16, 1944 2,413,533 Wainwright et a1. Dec. 31, 1946 2,556,580 Foxet a1 June 12,1951 2,668,362 P. Johnson Feb. 9, 1954 2,716,287 Hilst'rom Aug. 30, 1955 2,727,313 Wonders Dec. 20, 1955 

